When you eat food, it is processed and nutrients are absorbed as it courses through the intestine to finally become stool. The transit time of stool in the intestine can vary depending on the concentrations of the various electrolytes that affect the function of intestinal muscles and nerves. Constipation refers to increased difficulty and strain involved in passing stool; there is also decreased frequency of stool passage.
Causes of Constipation
Constipation can result from an abnormality in the ions involved in contraction and relaxation of intestinal muscle. Damage to nerves that stimulate intestinal muscle contraction can lead to constipation. Decreased water intake and a low fiber diet increase the likelihood for constipation. Constipation in an elderly male raises concern for colon cancer.
Complications of Constipation
Chronic constipation stretches the intestinal wall and increases the pressure in the venous circulation around the intestine. Veins are compliant vessels, meaning that they stretch to accommodate increases in pressure, but do not return to their previously un-stretched state; chronic constipation causes hemorrhoids or dilated vessels. Fecal matter can accumulate and harden over time due to chronic constipation.
Low potassium can cause constipation. There is a constant outflow of potassium from the intestinal muscle cell to the outside of the cell. When blood potassium is low, more potassium leaves the cell. As more potassium flows out of the cell, it makes the cell more resistant to the transmission of current across its membrane and therefore, less likely to contract and move stool efficiently. Low magnesium is also associated with low potassium and therefore, may cause constipation. Low calcium can be accompanied by low magnesium, but is not a cause of constipation; high calcium leads to constipation.
Management of Constipation
If you suspect that you have constipation, increasing water intake and dietary fiber intake are ways of mitigating the discomforts. Laxatives, enemas or suppositories may be needed for more troublesome constipation. Avoid excessive straining during defecation, as this this can lead to the development of hemorrhoids.